The invention relates to a portable telephone having a casing and a flap pivotable relative to the casing.
The flap can assume various angular positions relative to the casing between two extreme positions:
a retracted position, in which the flap is retracted against the casing, for example to cover an alphanumeric keypad; and
a deployed position, in which the flap is at an angle of substantially 180xc2x0 to the casing.
The flap generally protects the keys in the retracted position and allows access to them in the deployed position.
The portable telephone also includes means for sensing the position of the flap and a switch connected to the sensing means to select an xe2x80x9coff-hookxe2x80x9d mode enabling a telephone call to be conducted when the flap is in the retracted position or an xe2x80x9con-hookxe2x80x9d mode interrupting the telephone call in progress when the flap is in the retracted position.
The expression xe2x80x9cportable telephonexe2x80x9d refers to any type of cordless telephone, for example telephones which are connected by radio to a base station connected to a public switched network, and to cellular telephones of a mobile telephone network, in particular a GSM network.
Many portable telephones have a xe2x80x9chands-freexe2x80x9d mode enabling a call to be conducted without the user having to hold the telephone near the ear or mouth.
The sound level of the telephone is amplified so that the user can hear the conversation comfortably.
It is therefore essential for the hands-free mode to be activated only if the telephone is away from the ear or mouth.
Fixed systems are available, in particular for use in vehicles, which automatically select the hands-free mode immediately the telephone is placed on the fixed system.
However, this has the disadvantage of requiring the presence of an additional device.
In the absence of such fixed systems, the hands-free mode is activated or de-activated by selecting it using a key or a specific menu.
This is complicated, however, and activation is not automatic.
Other portable telephones have an infrared sensor adapted to sense the distance between the telephone and the user""s mouth or ear. Threshold distances condition activation or de-activation of the hands-free mode.
Those telephones have the drawback of requiring additional components, which increases their size and cost.
The object of the invention is therefore to eliminate the above drawbacks.
To this end, it proposes a portable telephone of the aforementioned type wherein the switch further includes means for selecting a xe2x80x9chands-freexe2x80x9d mode when the flap is in a particular intermediate position.
Because this intermediate position of the flap during a call is uncomfortable for the user, it automatically causes the user to hold the telephone away from the head while the xe2x80x9chands-freexe2x80x9d mode is activated.
In one particular embodiment of the invention, in the intermediate position the flap is at an angle of substantially 60xc2x0 to 120xc2x0 to the casing.
The means for sensing the position of the flap relative to the casing can be mechanical and/or electromagnetic.
The invention also provides a method of controlling a xe2x80x9chands-freexe2x80x9d circuit of a portable telephone having a casing and a flap pivotable on the casing between a retracted position and a deployed position, wherein the xe2x80x9chands-freexe2x80x9d circuit is activated when the flap is in a particular intermediate position and the xe2x80x9chands-freexe2x80x9d circuit is de-activated when the flap is in the retracted position or the deployed position.